INT 16 U - PCIBM PC Tools v9 DSKLIGHT - INSTALLATION CHECK
	AX = FFA3h
	BX = FFA3h
	CX = FFA3h
Return: BX = CX = 5555h if installed
	    AX = resident code segment
Program: DSKLIGHT is a TSR(Terminate and Stay Resident) A program which remains in memory after terminating in order to provide services to other programs or the user.  The name comes from the name of the DOS function call used to remain in memory after termination. included with PCIBM PC Tools v9+ which displays a disk-
	  access indicator on the screen; in v7 and v8, this function was
	  provided by DATAMON
Note:	DSKLIGHT chains to the previous handler if BX or CX is not FFA3h